Dynamics of Nonlinear Random Walks on Complex Networks

In this paper we study the dynamics of nonlinear random walks. While typical random walks on networks consist of standard Markov chains whose static transition probabilities dictate the flow of random walkers through the network, nonlinear random walks consist of nonlinear Markov chains whose transition probabilities change in time depending on the current state of the system. This framework allows us to model more complex flows through networks that may depend on the current system state. For instance, under humanitarian or capitalistic direction, resource flow between institutions may be diverted preferentially to poorer or wealthier institutions, respectively. Importantly, the nonlinearity in this framework gives rise to richer dynamical behavior than occurs in linear random walks. Here we study these dynamics that arise in weakly and strongly nonlinear regimes in a family of nonlinear random walks where random walkers are biased either towards (positive bias) or away from (negative bias) nodes that currently have more random walkers. In the weakly nonlinear regime we prove the existence and uniqueness of a stable stationary state fixed point provided that the network structure is primitive that is analogous to the stationary distribution of a typical (linear) random walk. We also present an asymptotic analysis that allows us to approximate the stationary state fixed point in the weakly nonlinear regime. We then turn our attention to the strongly nonlinear regime. For negative bias we characterize a period-doubling bifurcation where the stationary state fixed point loses stability and gives rise to a periodic orbit below a critical value. For positive bias we investigate the emergence of multistability of several stable stationary state fixed points

Synchronization of phase oscillators on complex hypergraphs

We study the effect of structured higher-order interactions on the collective behavior of coupled phase oscillators. By combining a hypergraph generative model with dimensionality reduction techniques, we obtain a reduced system of differential equations for the system's order parameters. We illustrate our framework with the example of a hypergraph with hyperedges of sizes 2 (links) and 3 (triangles). For this case, we obtain a set of 2 coupled nonlinear algebraic equations for the order parameters. For strong values of coupling via triangles, the system exhibits bistability and explosive synchronization transitions. We find conditions that lead to bistability in terms of hypergraph properties and validate our predictions with numerical simulations. Our results provide a general framework to study synchronization of phase oscillators in hypergraphs, and they can be extended to hypergraphs with hyperedges of arbitrary sizes, dynamic-structural correlations, and other features.Comment: 8 pages, 5 figure

A comparative study between the use of the combination of trichloroacetic acid peeling with hydroquinone and hydroquinone alone in patients with melasma

Background: Melasma is a common acquired pigmentary disorder that is aesthetically displeasing. Kligman’s and Modified Kligman’s formula using topical steroids, hydroquinone and retinoids, and various other depigmenting agents is being widely used all over for melasma with varying results. Chemical peeling is newly added to the therapeutic armamentarium and is showing encouraging results worldwide in patients with melasma. However, comparative studies are lacking in abundance in our part of the world. Aims and Objectives: To determine if serial trichloroacetic acid peels provide additional benefits when combined with time-tested topical therapy with hydroquinone 4% in patients with melasma. Materials and Methods: Fifty melasma patients were divided into two groups of 25 each. One group received serial trichloroacetic acid peel combined with topical hydroquinone 4%. The other group only received topical hydroquinone 4% cream. The results were evaluated by a clinical investigator both subjectively and with photographs taken at baseline, 12 weeks, and 21 weeks. For clinical evaluation, the melasma area and severity index (MASI) was used. Results: A significant decrease in MASI score from baseline to 21 weeks was observed in both groups (P<0.001). The group receiving the trichloroacetic acid peel 20% showed a trend toward more rapid and greater improvement, with statistically significant results (P<0.001). Only a few side effects were observed in the peel group. Conclusion: This study demonstrates that serial trichloroacetic acid peels provide an additional effect to a topical regimen of 4% hydroquinone cream for treating melasma in Fitzpatrick skin types III and above if used judiciously and under supervision. It demonstrates that superficial chemical peels can be used as an adjunct with better efficacy to treat patients with melasma

Porous activated carbon materials from Triphala seed stones for high-performance supercapacitor applications

Porous activated carbon materials derived from biomass could be the suitable materials for high-rate performance electrochemical supercapacitors as it exhibits high surface area due to well-defined pore structure. Here, we report the novel porous activated carbon from Triphala seed stones by chemical activation with zinc chloride at different carbonization temperature (400-700 °C) under the nitrogen gas atmosphere. The activated carbon was characterized by Fourier transform-infrared (FTIR) spectroscopy, Raman scattering and scanning electron microscopy (SEM). Nitrogen adsorption-desorption measurements was used to study the surface properties (effective surface areas, pore volumes and pore size distributions). The electrochemical measurements were performed in an aqueous 1 M sulphuric acid (H2SO4) solution in a three-electrode cell set up. Triphala seed stones-derived porous carbon materials with well-defined micro- and mesopores exhibit high specific surface area ranges from 878.7 to 1233.3 m2 g-1 and total pore volume ranges from 0.439 to 0.626 cm3 g-1. The specific capacitance obtained by electrochemical measurement experiment was 208.7 F g-1 at 1 A g-1. These results indicate that the prepared nanoporous activated carbon material from Triphala seed stones would have significant possibility as supercapacitor electrode material for high-energy-storage supercapacitor applications

High-throughput bacterial SNP typing identifies distinct clusters of Salmonella Typhi causing typhoid in Nepalese children.

BACKGROUND: Salmonella Typhi (S. Typhi) causes typhoid fever, which remains an important public health issue in many developing countries. Kathmandu, the capital of Nepal, is an area of high incidence and the pediatric population appears to be at high risk of exposure and infection. METHODS: We recently defined the population structure of S. Typhi, using new sequencing technologies to identify nearly 2,000 single nucleotide polymorphisms (SNPs) that can be used as unequivocal phylogenetic markers. Here we have used the GoldenGate (Illumina) platform to simultaneously type 1,500 of these SNPs in 62 S. Typhi isolates causing severe typhoid in children admitted to Patan Hospital in Kathmandu. RESULTS: Eight distinct S. Typhi haplotypes were identified during the 20-month study period, with 68% of isolates belonging to a subclone of the previously defined H58 S. Typhi. This subclone was closely associated with resistance to nalidixic acid, with all isolates from this group demonstrating a resistant phenotype and harbouring the same resistance-associated SNP in GyrA (Phe83). A secondary clone, comprising 19% of isolates, was observed only during the second half of the study. CONCLUSIONS: Our data demonstrate the utility of SNP typing for monitoring bacterial populations over a defined period in a single endemic setting. We provide evidence for genotype introduction and define a nalidixic acid resistant subclone of S. Typhi, which appears to be the dominant cause of severe pediatric typhoid in Kathmandu during the study period

Effect of Hydrocortisone on Mortality and Organ Support in Patients With Severe COVID-19: The REMAP-CAP COVID-19 Corticosteroid Domain Randomized Clinical Trial.

Importance: Evidence regarding corticosteroid use for severe coronavirus disease 2019 (COVID-19) is limited. Objective: To determine whether hydrocortisone improves outcome for patients with severe COVID-19. Design, Setting, and Participants: An ongoing adaptive platform trial testing multiple interventions within multiple therapeutic domains, for example, antiviral agents, corticosteroids, or immunoglobulin. Between March 9 and June 17, 2020, 614 adult patients with suspected or confirmed COVID-19 were enrolled and randomized within at least 1 domain following admission to an intensive care unit (ICU) for respiratory or cardiovascular organ support at 121 sites in 8 countries. Of these, 403 were randomized to open-label interventions within the corticosteroid domain. The domain was halted after results from another trial were released. Follow-up ended August 12, 2020. Interventions: The corticosteroid domain randomized participants to a fixed 7-day course of intravenous hydrocortisone (50 mg or 100 mg every 6 hours) (n = 143), a shock-dependent course (50 mg every 6 hours when shock was clinically evident) (n = 152), or no hydrocortisone (n = 108). Main Outcomes and Measures: The primary end point was organ support-free days (days alive and free of ICU-based respiratory or cardiovascular support) within 21 days, where patients who died were assigned -1 day. The primary analysis was a bayesian cumulative logistic model that included all patients enrolled with severe COVID-19, adjusting for age, sex, site, region, time, assignment to interventions within other domains, and domain and intervention eligibility. Superiority was defined as the posterior probability of an odds ratio greater than 1 (threshold for trial conclusion of superiority >99%). Results: After excluding 19 participants who withdrew consent, there were 384 patients (mean age, 60 years; 29% female) randomized to the fixed-dose (n = 137), shock-dependent (n = 146), and no (n = 101) hydrocortisone groups; 379 (99%) completed the study and were included in the analysis. The mean age for the 3 groups ranged between 59.5 and 60.4 years; most patients were male (range, 70.6%-71.5%); mean body mass index ranged between 29.7 and 30.9; and patients receiving mechanical ventilation ranged between 50.0% and 63.5%. For the fixed-dose, shock-dependent, and no hydrocortisone groups, respectively, the median organ support-free days were 0 (IQR, -1 to 15), 0 (IQR, -1 to 13), and 0 (-1 to 11) days (composed of 30%, 26%, and 33% mortality rates and 11.5, 9.5, and 6 median organ support-free days among survivors). The median adjusted odds ratio and bayesian probability of superiority were 1.43 (95% credible interval, 0.91-2.27) and 93% for fixed-dose hydrocortisone, respectively, and were 1.22 (95% credible interval, 0.76-1.94) and 80% for shock-dependent hydrocortisone compared with no hydrocortisone. Serious adverse events were reported in 4 (3%), 5 (3%), and 1 (1%) patients in the fixed-dose, shock-dependent, and no hydrocortisone groups, respectively. Conclusions and Relevance: Among patients with severe COVID-19, treatment with a 7-day fixed-dose course of hydrocortisone or shock-dependent dosing of hydrocortisone, compared with no hydrocortisone, resulted in 93% and 80% probabilities of superiority with regard to the odds of improvement in organ support-free days within 21 days. However, the trial was stopped early and no treatment strategy met prespecified criteria for statistical superiority, precluding definitive conclusions. Trial Registration: ClinicalTrials.gov Identifier: NCT02735707

Prospects of tourism in Nepal : A study of Pokhara city

The aim of this thesis is to analyse the possibilities of employment opportunities, growth in National income, tourism activities, attraction and challenges in tourism development in Pokhara city, using available resources and to promote Pokhara as the best touristic hub in Nepal. The objective behind this the-sis is to understand the potentiality of the tourism industry in Pokhara city through the collection of data and its analysis, and then provide information and relevant suggestions for the upliftment of tour ism in Pokhara. The Author has chosen this topic with the thought of pursuing her career in the field of tourism business in Pokhara, Nepal. The theoretical part of this thesis covers the introduction, general concept of tourism, history of tourism, tourism in Pokhara and its history, importance of tourism in the city of Pokhara, tourism activities, religious importance, culture, tourism statistics, economic impact and prospects of tourism, government and non-government bodies related to the development of tourism industry in Pokhara, tourist attractions in Pokhara and other tourism-related aspects and their prospects in the city of Pokhara. The objective of this thesis is to find out the possibilities of tourism industry development in near future. Moreover, this thesis reflects the importance of tourism in Pokhara and potentiality to growth in GDP, providing employment opportunity and promotes Pokhara as the best touristic destination of Nepal. Quantita-tive research method will be used to understand the needs and desire of visitors and to find out the possibili-ties of tourism development in the city. The acquired data and survey report also focus on understanding the possible factors that may influence the length of stay of the tourists in Pokhara, thereby helping create a fa-vourable environment for a prolonged stay of visitors

Ethno-medicinal Usage Ethno-medicinal Usage of Invasive Plants in Traditional Health Care Practices: A Review

Nepal is a small South Asian country with a varied geographical and bioclimatic landscape. Invasive Plant Species have already been introduced in large numbers, causing the extinction of native species and disrupting crop production, as well as degrading endangered animal habitats, changing plant species composition, and interfering with tree seedling regeneration. However, it is critical in the health treatment of rural populations in developing countries. Our study will look at and compile knowledge on the therapeutic applications of invasive plants utilized by a range of Nepalese communities. We combed through numerous websites, including Research Gate and Google Scholar, for historical and contemporary studies on the therapeutic usage of Nepal's invasive plants.24 species from 12 families of invasive alien plant species were identified to be utilized for medicinal purposes by Nepalese rural people. The 39 diseases for which medicinal plants were reported were diabetes, rheumatism, fever, ulcers, bronchitis, kidney stone, asthma, urinary insufficiency, and others. Traditional knowledge of invasive plant species' uses is diminishing due to the negative effects of invasive plant species on the ecosystem; hence, rigorous documentation of ethnomedicinal knowledge on invasive plant species is needed. Thus, the medicinal potentialities of unwanted invasive species, which are sometimes neglected by others, will provide a gem for the study world

Hypoplastic Left Heart Syndrome: A Case Report

Hypoplastic left heart syndrome is a rare critical congenital heart defect constituting a prevalence of 1/3,500 to 1/12,500 live births in which there is obstructions to the blood flow within the left heart. Here we present a case of a full-term 38 weeks male baby with a birth weight of 3.5 kg, and no obvious physical deformity referred to our centre at 22 hours of life for respiratory distress and cyanosis. At 23 hours of life, he was diagnosed with hypoplastic left heart syndrome and kept on Prostaglandin E1 infusion till the 12th day of life. The baby had a large ventricular septal defect and atrial septal defect with a severely hypoplastic left ventricle, hypoplastic aortic root, ascending aorta and post-ductal coarctation of the aorta. The diagnosis was reconfirmed by computed tomography cardiac angiography on the 10th day of life with the same cardiac findings suggestive of hypoplastic left heart syndrome